Student Experiments on SANDALS, ISIS

CDT-CMP Student Lawrence Gammond visited ISIS to complete an experiment on Small Angle Neutron Diffractometer for Amorphous and Liquid Samples (SANDALS). Here he explains why he was there and how the experiment went.


  1. The Instrument

Especially designed for investigating the structure of disordered materials, the Small Angle Neutron Diffractometer for Amorphous and Liquid Samples (SANDALS) at ISIS provides sub-Angstrom distance resolution out to a length scale of 30 Angstroms. This is ideal for pair distribution studies, which reveals information on the average separation and coordination environment of atomic species’ in materials.

  1. Magnesium Aluminosilicate

Mg-Aluminosilicate is commonly used in glass-ceramics and display glass. It is also a major constituent of the CaO-MgO-Al2O3-SiO2 (CMAS) family of crustal and mantle minerals, where the glass is often used as a proxy for the investigation of magmatic fluids. The role of Mg in these materials, however, is largely unknown.

The Experiment

To investigate the role of Mg in Mg-Aluminosilicates, neutron diffraction experiments were performed on a series of glasses with different compositions. The results will investigate the ability of Mg to act as different structural elements, where the difference can be seen in the coordination environment deduced from the diffraction data. Complimentary information has been provided by NMR studies on the same glasses, and future experiments are planned to take place at the ILL in France and at ISIS in the UK (next time will be on the high pressure instrument PEARL).